To Prevent Diabetes, Walk After Meals

A 15-minute walk after each meal may help older people control their blood sugar and could reduce their risk of developing type 2 diabetes, shows a study by researchers at the George Washington University School of Public Health and Health Services.

The study, published recently in Diabetes Care, found that three short post-meal walks were as effective at reducing blood sugar over 24 hours as a 45-minute walk of the same easy-to-moderate pace. Post-meal walking was also significantly more effective than a sustained walk at lowering blood sugar for up to three hours following the evening meal.

“These findings are good news for people in their 70s and 80s who may feel more capable of engaging in intermittent physical activity on a daily basis, especially if the short walks can be combined with running errands or walking the dog,” said lead study author Loretta DiPietro, chair of the SPHHS Department of Exercise Science. “The muscle contractions connected with short walks were immediately effective in blunting the potentially damaging elevations in post-meal blood sugar commonly observed in older people,” she said.

Other studies have suggested weight loss and exercise can prevent type 2 diabetes, but this is the first to examine short bouts of physical activity timed around the risky period following meals—a time when blood sugar can rise rapidly and potentially cause damage.

The findings, if confirmed by additional research, could lead to an inexpensive preventive strategy for a pre-diabetic condition that can over time develop into type 2 diabetes, Dr. DiPietro said. An estimated 79 million Americans have pre-diabetes but most have no idea they are at risk.

Dr. DiPietro and her colleagues recruited 10 people age 60 and older who were otherwise healthy but at risk of developing type 2 diabetes due to higher-than-normal levels of fasting blood sugar and low levels of physical activity.

Participants completed three randomly ordered exercise protocols spaced four weeks apart. Each protocol comprised a 48-hour stay in a whole-room calorimeter, with the first day serving as a control period. On the second day, participants engaged in either post-meal walking for 15 minutes after each meal or 45 minutes of sustained walking performed at 10:30 a.m. or at 4:30 p.m. Participants ate standardized meals and researchers measured their blood sugar levels continuously over each 48-hour stay.

The team observed that the most effective time to go for a post-meal walk was after the evening meal. The exaggerated rise in blood sugar after this meal—often the largest of the day—often lasts well into the night and early morning and this was curbed significantly as soon as the participants started to walk on the treadmill, Dr. DiPietro said.

The results of this study must be confirmed with larger trials that include more people, she said.